There are a vast number of ways for delivering an active agent, such as a drug, to the body. For example, the active agent can be delivered topically or can be ingested in pill form, etc. In addition, mechanisms for sustained release of the active agent over a predetermined period of time are also known.
One type of drug delivery device is an ocular drug delivery device that delivers an active agent to the eye. The idea of placing a solid device into or near the eye to deliver a drug or a lubricant over time is not new. Most recent scientific interest in this field stems from advances in surgical techniques, pharmacology and pharmacokinetics, as well as the availability of improved polymer systems that can be tailored to the specific needs of ocular drug delivery. For clarity, the distinction should be made between a device that is “inserted into the eye”, meaning placed under the eyelids, external to the eyeball itself, and traditionally referred to as an “ocular insert”, vs. a device that is inserted into the eye surgically, meaning an intraocular insert placed inside the eyeball, or partly inside the eyeball itself. In fact, some devices are implanted in the layers of connective tissue forming the globe of the eyeball, and may even extend through these layers into the eyeball. And some that could be inserted topically under the eyelids could also be surgically implanted under the outermost layer, the conjunctiva, anteriorly, or Tenon's capsule, posteriorly, and would correctly be referred to as subconjunctival or sub-Tenon's inserts. This would be done via a minimally invasive procedure that does not open into the eyeball itself, but rather into the space currently utilized by ophthalmologists for subconjunctival or sub-Tenon's injections.
While there are conventional ocular drug delivery devices that include a drug core holding drug for release, these devices are constructed such that the drug delivery device is formed with a recess (well) that receives a separate drug core. A release membrane is then disposed over the drug core in the situation where a delayed/sustained release profile is desired. This process for forming the drug delivery device is time consuming and has certain limitations and deficiencies as discussed herein.